1. Field of the Invention
This specification relates to a liquid type dehumidifying apparatus, and particularly, to a heat exchanger having an extended surface plate capable of effectively absorbing moisture from the air by using a dehumidifying liquid, and capable of having enhanced rigidity, and a liquid type dehumidifier having the same.
2. Background of the Invention
Generally, a liquid type dehumidifier serves to obtain dry air by absorbing moisture in the air by spraying a dehumidifying liquid of a high concentration to the air. This liquid type dehumidifier is configured to perform consecutive dehumidifying operations by circulating the dehumidifying liquid sprayed into the air to be dried. Here, the dehumidifying liquid having absorbed moisture in the air has a low concentration, thereby having a low hygroscopic property in the next cycle. To prevent this, the dehumidifying liquid which has become diluted after absorbing moisture is re-sprayed into the air of a high temperature, thereby having moisture evaporated therefrom at a high temperature atmosphere. This process is called ‘regeneration’, and is performed in a regenerator.
For enhanced dehumidifying efficiency, the dehumidifying liquid and the air to which the dehumidifying liquid is sprayed preferably have low temperatures. Furthermore, a contact area between the dehumidifying liquid and the air is preferably increased. For enhanced regenerating efficiency, the dehumidifying liquid and the air to which the dehumidifying liquid is sprayed preferably have high temperatures, and a contact area is preferably increased. In order to operate this liquid type dehumidifier, the dehumidifying liquid and the air have to be heated (regenerating process) or cooled (dehumidifying process). To this end, a heat exchanger is used. More concretely, a dehumidifying liquid is sprayed onto the surface of a heat exchanger in which a heat medium of a high temperature of a low temperature flows so that the dehumidifying liquid can flow along the surface of the heat exchanger. And, air is sprayed onto the heat exchanger so that the air and the dehumidifying liquid can be cooled or heated by being heat-exchanged with the heat medium which flows in the heat exchanger. In order to cool or heat a larger amount of dehumidifying liquid for a unitary time, a larger amount of dehumidifying liquid has to be firstly supplied. However, in this case, the dehumidifying liquid may form a thick liquid film on the surface of the heat exchanger. This may lower a heat and mass transfer coefficient. Furthermore, when a thick liquid film is formed on the surface of the heat exchanger, waves may be formed on the surface of the liquid film or the liquid film may become unstable. This may cause the liquid film to be dispersed to the supplied air.
FIG. 1 illustrates an example of the heat exchanger. Referring to FIG. 1, the heat exchanger 10 has a structure in which a plurality of heat exchanging bodies 12 are disposed in parallel. Cooling water or heating water for heat exchange flows to an inner space of each heat exchanging body 12. The inner space is divided into a plurality of channels by partition walls 14. A dehumidifying liquid is supplied to upper parts of the heat exchanging bodies 12, and downward flows along the surfaces of the heat exchanging bodies 12 by gravitation. Air to be dehumidified or regenerating air is supplied to a space between the heat exchanging bodies 12.
Under this configuration, the dehumidifying liquid and the air are heated or cooled to enhance dehumidifying efficiency or regenerating efficiency. In order to enhance heat transfer efficiency, the dehumidifying liquid has to be uniformly supplied onto the surfaces of the heat exchanging bodies 12. And, the liquid film formed on the surface of the heat exchanger has to have a thin thickness. This is may increase a heat transfer amount to the air, and may prevent the dehumidifying liquid from being dispersed to the air.
The dehumidifying liquid and the air are heat-exchanged only on the surfaces of the heat exchanging bodies 12. This may cause the heat exchanger to have a large size. Furthermore, a heat transfer amount per unitary time is decreased due to a limited thickness of the liquid film.
To prevent this, as shown in FIG. 2, the present inventor has devised a structure in which each of extended surface plates 50 is disposed in a zigzag form between the heat exchanging bodies 12. This may prolong time taken for a dehumidifying liquid supplied from the upper side to stay between the two heat exchanging bodies, thereby enhancing contact efficiency.
However, as shown in FIG. 3, when the extended surface plates 50 are not installed in a completely horizontal state, a dehumidifying liquid may be collected to a lower side along an inclination in spite of a very small gradient. This may cause the dehumidifying liquid not to uniformly spread onto the surfaces of the extended surface plates 50. As a result, a contact area between the dehumidifying liquid and the air is decreased, and dehumidifying efficiency is degraded.
The extended surface plate 50 is formed of nonwoven fabric so that a dehumidifying liquid can be easily soaked thereto. However, when the nonwoven fabric has a wet surface by the dehumidifying liquid, an intensity of the extended surface plate may be degraded due to a weight of the dehumidifying liquid. This may cause the extended surface plate extending in parallel between the heat exchanging bodies to have a downward deformed center as shown in FIG. 2. Furthermore, the dehumidifying liquid may be collected in the downward deformed center, not on the entire surface of the extended surface plate. As a result, heat exchange efficiency between the dehumidifying liquid and the air may be lowered.
In order to solve this problem, the extended surface plate 50 is made to maintain a complete horizontal state, or an additional reinforcing structure is adopted, or a material having a higher intensity is used. However, this may cause the entire structure to become complicated, or degrade a wet property.